Due to the high demand for hydrocarbons, the quality of the petroleum extracted worldwide has declined with the passage of time, since the hydrocarbons considered of high quality known as light crude oils, characterized by its greater amount of gasoline, low resin and low sulphur become limited, increasing the need for using the deposits of heavy crude oils that are distinguished by a greater proportion of undesirable components, such as sulfur, nitrogen, oxygen and metals, which produce greater amounts of pollutants and complicate the refining process.
In addition, the great technological and environmental problems generated by the presence of sulphur in the hydrocarbons combustion, have required current laws of developed countries to demand for low sulphur content in fuels such as gasoline and diesel, reducing the permitted sulphur content dramatically in a few years, reaching levels of 10 ppm in 2010.
The legislation to regulate the sulphur content allowed in fuels, together with the raw material processing of increasingly lower quality, has generated great difficulties in the hydrotreatment processes, wherein current catalysts have not been able to meet the strict requirements, being unable to treat more refractory molecules and as a result it is practically impossible for these to reach the imposed laws; consequently the need for the use of catalysts with optimized properties or new more active and selective catalysts are currently the greater challenge.
The hydroprocessing or hydrotreatment (HDT) processes, encompassed in the petroleum refining industry, wherein usually the separation of the highest proportion of contaminants is carried, have been using transition metal sulfides catalysts. More specifically, for a long period of time molybdenum has been the material in which the investigation of HDT has been focused. Currently, the science for the HDT catalysts and more specifically for hydrodesulfurization (HDS), has advanced a lot for the understanding of molybdenum based catalysts. Thus, emerging bimetallic catalysts, trimetallic catalysts, and the last generation of unsupported catalysts called NEBULA, with very complex synthesis processes but which offer considerable advantages over their predecessors. However, the exhaustive removal of heteroatoms in heavy fractions of petroleum remains a challenge, since it has been found that conventional catalysts for HDT are not sufficiently effective for this purpose.
In studies conducted by Pecoraro T. A., Chianelli R. R., 1981. Journal of Catalysis, 67 Issue 2, pp. 430-445; Shafia R., Hutchings G. J., 2000. Catalysis Today, 59 pp. 423-442; Grange P., Vanhaeren X., 1997. Catalysis Today, 36, pp. 375-391; Chianelli R. R., Berhault g., Raybaud P., Kasztelan S., Hafner J., H. Toulhoat, 2002. Applied Catalysis A: General, 227, pp. 83-96 and Chianelli R. R., Berhault G., B. Torres, 2009. Catalysis Today, 147, pp. 275-286, have show that unsupported ruthenium sulfide is a material that presents high activity, surpassing the traditional molybdenum sulfide catalyst and making it an excellent candidate to meet current requirements.
It is well known that the catalytic properties of a material depend greatly from its synthesis, as in the case of the catalysts called STARS, where an appropriate impregnation method allows a considerable improvement in the catalytic activity of the material (Song C., 2003. An overview of new approaches to deep desulfurization for ultra clean gasoline, diesel fuel and jet fuel. Catalysis Today, 86, pp. 211-263). It is why the features of the catalyst are of vital importance for their performance in the catalysts; thus, catalysts with low crystallinity (greater amount of defects which are usually active sites), high surface area (most exposed active sites) usually affect the catalytic activity of the material, resulting in materials being catalytically more active. These characteristics are obtained in the material synthesis; it is for this reason that starting from an appropriate precursor and with an appropriate decomposition/activation method, it is possible to generate a sulfide ruthenium catalyst with high catalytic activity.
The best catalysts in the HDS at the end of XX century were catalysts of sulfide of cobalt and molybdenum supported in alumina commonly known as CoMo/Alumina; nevertheless, Exxon Mobil-Albernate reported a new generation of commercial catalysts called STARS (Sites of Super Active Reaction Type II) which are catalysts of CoMo/Alumina and NiMo/Alumina, that are synthesized using a new alumina support base and a special technique of incorporation of the promoter (Co or Ni) which allows a very great and uniform dispersion of the metals in the support with moderate density. This catalysts family quickly exceeded the traditional CoMo/Alumina catalysts due to their capacity of sulphur removal especially steric hindered molecules (Song C., 2003. An overview of new approaches to deep desulfurization for gasoline, diesel engine fuel and jet fuel. Catalysis Today, 86, pp. 211-263). Subsequent to this great advance in the catalysts synthesis technology, at the beginning of this decade Exxon Mobil-Albemarle showed a similar development to the obtained by the STARS catalysts which were obtained thanks to the new catalyst called NEBULA (New Bulk Activity), which is an unsupported catalyst of NiCoMo without the use of a support, that allows a high performance in the quality of products like low sulphur content, high cetane, low density, etc. (Soled, Stuart L., Miseo, Sabato, Krycak, Roman, Vroman, Hilda, Ho, Teh C., Riley, Kenneth L., 2001. Nickel molybodtungstate hydrotreating catalysts (law444). U.S. Pat. No. 6,299,760; Meijburg G., 2001. Production of Ultra-low-sulfur Diesel in Hydrocracking with the Latest and Future Generation Catalysts. Catalyst Courier, 46, Akzo Nobel; Song C., 2003. An overview of new approaches to deep desulfurization for ultra-clean gasoline, diesel engine fuel and jet fuel. Catalysis Today, 86, pp. 211-263).
In summary, due to the legal requirements, technological and environmental, which reduce more and more the level of fuel emissions mainly allowed in combustibles, the generation of a more efficient catalytic system in HDS is the challenge. Currently, the catalysts used at the industrial level are based on molybdenum, supported and promoted by one or more transition metals (TM). Considering these regulations and the characteristics of the present catalysts, it becomes evident that the development of a new catalysts family with high catalytic activity is necessary. The most direct option is with the synthesis of ruthenium based catalysts. In this sense, a catalyst that offers high catalytic activity with a simple synthesis method may be the solution to the problems faced by the petrochemical industry.
Complex ruthenium precursors and other metals have been successfully synthesized thanks to the facility that presents the metals to form complexes. Thus, different ruthenium complex compounds have been synthesized and patented such as:
The United States Patent Publication Application No. 20030045737 that shows the synthesis of ruthenocene, ruthenocene cyclopentadienyl or indenyl ruthenocene, from a cyclopentadienyl compound or indenil with ruthenium chloride III hydrated and magnesium dust.
The U.S. Pat. No. 7,893,290 that shows the synthesis of an organometallic complex with formula M(RPD)2, where M is iron, ruthenium or osmium; R is hydrogen or an aryl group with 1 to 4 carbon atoms and PD is a cyclic or open chain of a dienyl system that forms a complex type sandwich. This precursor is used to make thin films.
U.S. Pat. No. 7,928,257 shows a method for the production of a ruthenium complex of formula (Ru(Salen)(CO) of very complex structure for optical uses.
U.S. Pat. No. 7,928,257 shows the synthesis of organometallic complexes of very complex structures with cyclic compounds, radical groups, nitrogen and ligands, these complexes types have important applications in electroluminescence devices.
U.S. Pat. No. 7,812,251 shows the synthesis of a transition metal complex of formula MLY1, where M is a transition metal like ruthenium, L is binding of polypyridine and Y1 is a functional group that can have more than 50 carbon atoms, nitrogen or oxygen. This complex has important uses in photovoltaic cells.
Also the ruthenium complexes have been used as catalytic and we found the following patent documents:
U.S. Pat. No. 7,880,025 shows a method to produce a ruthenium complex of formula [RuX2 (L1)]2 where X represents a halogen atom and L1 represent an aromatic complex compound with 8 radical groups. With uses in catalysts for the hydrogenation process.
U.S. Pat. No. 7,932,411 shows a method to produce an  ruthenium complex with formula [RuX2 (L2)]n where X represents a halogen atom, L2 represents an aromatic compound and n is a natural number of 2 or more. Starting from the reaction of [RuX2(L1)]2 (U.S. Pat. No. 7,880,025) and L2. This ruthenium complex is also applied for the catalytic process of hydrogenation.
U.S. Pat. No. 7,772,445 shows a process for the reduction of composed with double carbon oxygen bond from a complex ruthenium-aryl-aminophosphine complex in the presence of a base. The ruthenium compound follows formula [RuX(A)(PNH2)]X where A is C6-14 an aryl or heteroaryl or an aromatic group of substituted C6-10, (PNH2) represents an aminophosphine ligand of formula R3R4P-L-NH2, where R3, R4 and L are radical complexes.
U.S. Pat. No. 6,426,437 shows a process to produce 1,4-butanediol with catalyst of rhodium complex, ruthenium complex and bidentate diphosphine ligand, wherein the ruthenium complex includes a ruthenium link to a ligand of the group of halides, hydrides, carbonyl, trialkyl or triaryl, phosphines, 2-4 alkanedionates and replaced and not replaced cyclopentadienyl.
U.S. Pat. No. 5,997,840 shows a method for the synthesis of a solid chiral catalyst of Zeolite BEA as support and a metal-binap complex. The complex can be of ruthenium or other metals and includes in a complex of 2,2′bis(diphenylphosphino)-1,1′-binaphthyl))-M(R) where R can be an enantiomer. Finding good activity for production of pure enantiomers.
United States Patent Application Publication No. 20100292486 shows an organometallic complex compound synthesis of ruthenium as highly active catalysts for ring-closing metathesis (RCM), rings-opening (ROM) and cross methateses (CM) reactions, these compounds are synthesized from monomeric molecules with ligands that contain substitute molecules as 1,3-dimesithyl-4,5-dihydroimidazol-2-ylidene and styrenyl to ether ligands.
U.S. Pat. No. 6,696,608 shows a process for the transference of hydrogen with a complex catalyst with transition metals of transition of the VIIIB.
United States Patent Application Publication No. 2010/0167915 shows a nanocatalyst synthesis for hydrodesulfuration where the support is a nano-structured porous carbonaceous compound, as: carbon nanotubes, carbon nano-fibers, carbon nanoporous, carbon nano-norn, carbon nano-tubes fibers, or any combination of them with at least a metal of VIIIB family and one of the 6B family and although never mentions to ruthenium, claims the VIIIB family.
United States Patent Application Publication No. 20100193402 shows the synthesis of a catalytic metal oxide composite, which is designed of at least a metal of group VIIIB and at least two metals of group VIB. Basically, they are trimetallic catalysts that claims the VIIIB family.
U.S. Pat. No. 7,754,068; the patent applications of the same country, the 201000288494 and 20100230323 and WO2011014553, claim the use of catalysts of VIB and VIIIB families without mentioning the ruthenium.
In the present invention synthesizes a ruthenium complex compound to be used as a precursor for the synthesis of catalysts for the HDS of hydrocarbons.
Thus, the present invention from the commercial point of view represents great advantages for having a very simple synthesis method of the precursory ruthenium complex which will affect in the catalyst cost, which is decomposed and activated by a process and infrastructure typically used for the activation of conventional catalysts; these two simple steps provide a catalyst with very high catalytic activity that allows to reach the high imposed requirements.
The catalytic activities achieved by the present invention are superior to the industrial catalyst, even greater than the current most active commercial unsupported catalyst.